This invention relates to propulsion pods having rim-driven blade sets for propelling marine vessels.
Conventional propulsion pods with rim-driven blade sets for marine vessels are subject to vibrations produced by turbulence in the water passing through the pod which may be excessive and may be transmitted to a vessel being propelled and also may be subject to wear of the parts supporting the rotating blade sets.
The Veronesi et al. U.S. Pat. No. 5,252,875 discloses a propulsion pod containing a permanent magnet motor driving a rotating blade set and having a rotor rim surrounding the blade set embedded in the surrounding structure so that it is out of the flow path of water through the pod and providing circulation of water through the space between the rotor and the stator from the high pressure side of the rotor to the low pressure side. That arrangement also provides stationary vanes following the rotating blade set to minimize swirling of the water driven by the blade set and also minimize cavitation and enhance efficiency.
U.S. Pat. No. 5,408,155 to Dickinson discloses a propulsion pod containing a rotor having radial and thrust bearing assemblies with engaging hard surfaces on both rotating and stationary components.
The Veronesi et al. U.S. Pat. No. 5,205,653 discloses a propulsion pod containing a rotor and a circular array of pivoting support members in an adjacent stationary part having thrust bearing surfaces for engagement with an adjacent surface of the rotor.